May 4, 2017
Someone might not expect to find an aggregate operation on top of a mountain in the middle of the Nevada desert, but that’s exactly where you’ll find Sloan Quarry, 19 miles south of downtown Las Vegas. Aggregate Industries (AIUS), part of the LafargeHolcim Group, purchased the quarry in 2004 and has turned it into the third largest quarry in the state.
“The limestone quarry of about 1,000 acres sits atop Sloan Mountain,” says Garry Priest, aggregate sales representative for AIUS’ Southwest Region. “It’s really the footprint of the quarry. We’ve done a lot of benching, which requires constant analysis of the deposit.”
Before AIUS purchased the operation, the mountain was being mined internally and rail cars carried the material down the side of the mountain to the plant below. There were also kilns on site because most of the material being mined was sent to the gold mines in the north.
Now, Priest explains that most of what is produced at the mine is used in asphalt and concrete. “The quality of our aggregates (absorbency and hardness) enables us to produce a wide range of asphalt products,” he says.
“We run three shifts here,” says Rick Hancock, operations manager at Sloan Quarry. “We run a day shift, which starts at 4 a.m. and ends at 2 p.m. The maintenance shift comes in at noon and works until 8 p.m. The night shift runs from 7 p.m. to 4 a.m.
“The facility produces about 2 million tons a year,” Hancock adds. “We’re bringing the mountain down from about 3,800 feet to subterranean. There’s a lot of reserve, so we’ll be producing quality aggregates for decades to come.”
Drilling and blasting operations take place multiple times a week. They drill and blast 4,400 feet per week, or approximately 62,000 tons of material, which is required to feed the plant. Loaders load the material into haul trucks for transport to the 1,300-ton-per-hour gyratory crusher, which takes the material from a 12-inch-plus rock to an 8-inch-minus rock.
The material then goes into a surge pile that feeds the secondary plant, which is capable of processing approximately the same amount as the gyratory. In the secondary, the 8-inch-minus rock is reduced to 1 1/2-inch minus and transferred to the secondary surge pile, which feeds the three plants at the base of the mountain. One is a dry plant that supplies all the materials for the on-site asphalt facility. The other two plants make washed concrete rock and sand for ready-mix customers.
Water used for washing comes from two wells on site. “Our two wells supply enough water for the plant until we hit the hot months of summer. Then we struggle a bit,” Hancock notes. “We’re looking at drilling another one, hopefully, this year.”
All minus-100 mesh goes to a filter press where the water is squeezed out, retrieved, and recirculated back to the wash plant. The filter press operator usually does 28 pressings per day, approximately 1,200 tons. When the dry cakes from the filter press are ready, they drop onto a conveyor, which carries them to a stockpile area. Prior to installing the filter press in 2009, fines were discharged into settling ponds.
Multiple on-site loaders feed material to the asphalt plant and on-site ready-mix facilities. They also load numerous customers in the marketplace.
“If the job site is close to Sloan Quarry, we’ll pick up business for various things,” Priest explains. “We touch anything from base to decorative boulders. A lot of people like the white color of our material, so the resale yards and nurseries buy it and label it as a “Spring Mountain White.”
One major project that Sloan Quarry is supplying material for is the Las Vegas ‘Weir’ project that has been going on for 10 years. The city is building 16 weirs throughout the city to help control erosion and filter stormwater before it goes into Lake Mead.
“They started doing it to stop erosion,” Hancock explains. “We take 4- or 5-foot boulders and stack them in cases 20 feet tall to build the weir. When the water hits it, it percolates down through the weir and comes out the bottom. The weirs slow the water down and reclaim it, so as much as possible can be put back into Lake Mead, which supplies water to 98 percent of Las Vegas.”
Another major project that the quarry is involved in is called ‘Project Neon.’ The ‘Spaghetti Bowl,’ where Interstate 15 intersects with Interstate 95 and another highway, is being revamped. Sloan Quarry has a multi-million-dollar contract to supply materials for various parts of the project.
Sloan Quarry has operated for more than 4,500 days without a lost time incident, which speaks highly of its safety program. It also received an award for no injuries from the governor of Nevada in September 2016.
At weekly safety meetings, information from the safety department is shared and near-miss incidents are discussed. MSHA refresher training takes place at the quarry every year, and additional training classes cover topics such as fall protection, energy isolation, lock-out/tag-out, and how to properly and safely splice conveyor belts.
“Obviously, safety is first and foremost here,” Hancock states, adding that he and the supervisors spend a lot of time out in the plant talking with the employees, vendors, and customers. “We’ve established a safety culture where we look out for each other. We empower our people to do the right thing and be safe, and let them know that they aren’t going to get in trouble if they push the stop button to shut down jobs or shut down their tasks if they don’t feel comfortable. It’s just part of the way we do business.”
When new people are hired, before they ever go out to the quarry, they spend six to eight hours training at the company’s main office with LaMar Martin, the company’s health and safety coordinator. Once at the quarry, another four hours are spent doing site-specific induction training — recognizing potential hazards around the mine site. Before new employees are permitted to work on their own, they are teamed up with one of the more experienced workers at the quarry for another eight to 24 hours, so they receive direct oversight.
“We assess all risks before starting any task,” Martin notes. “Our employees, vendors, and subcontractors all do Job Hazard Analysis (JHA) to look at what they’re supposed to do before they do it. They write it down and record it, and they are documented and reviewed by the supervisor.”
Martin adds that the employees don’t do any task for which they aren’t authorized. “If they haven’t been task trained on a particular piece of equipment, regardless of what anyone else says, they don’t get on it,” he says. “It gives them a bit of empowerment.”
“We take safety very serious,” Hancock explains. “We train and train, and then do some more training. I want my employees to go home to their families every night. It’s the most important thing to me in the business. It’s just how we operate.”
Supporting the community
Sloan Quarry is located 19 miles south of downtown Las Vegas, but the city’s population has been creeping steadily closer. There’s a very affluent neighborhood, Southern Highlands, with multi-million dollar homes just to the north of the quarry.
“We are careful about how we do what we do,” Priest says, explaining that they keep the community abreast of what’s going on at the quarry. “We have good relations with Southern Highlands. We shape the mountain a certain way to make it look good. Unless you know what you’re looking at, you don’t know it’s there.”
“The local desert environment is susceptible and can be challenging to control airborne emissions,” says Kathryn Hites, regional environmental and land manager for AIUS. “We work hard to address this issue through different controls, like continual watering of haul roads and stockpiles.”
Despite these challenges, Aggregate Industries makes every effort to be a good neighbor and responsible steward. For example, the secondary and overland conveyors have dust collectors to help control the dust, and the conveyors have water nozzles to keep the material damp enough to prevent it from becoming airborne. An environmentally friendly binder is used on the haul road to help seal it, and three water trucks spray throughout the plant site.
Construction notices for high-wind advisories are issued when conditions warrant. When that happens, Hancock says they shut down operations on top of the mountain and the overland conveyor, and just operate from the surge piles at the wash plant.
The quarry also supports local charities, such as the Boys & Girls Club, and participates in an annual fund-raising event known as the Fall Festival, which is put on by the Southern Highlands community.
Sloan Quarry works with the Nevada Mining Association by offering quarry tours. “They bring in local school teachers to tour the site,” Hancock says. “It’s good to be a part of it. I’ve been mining for 20 some-odd years, and you get a bad rap until somebody comes out and actually sees the good things you’re doing.”
“We also bring in an elementary school and take the kids up on the mountain so they can get an overview of what we do at the quarry,” Hites adds. “We take them out to see the 777, which they get a kick out of. We try to keep the community involved in what we do because we want to keep our neighbors happy.”
The quarry also works closely with engineering groups from the University of Nevada Las Vegas (UNLV), the largest college campus in southern Nevada. Priest says they never know what to expect from the university. Occasionally, materials are provided for a UNLV research project, and sometimes they want to tour the quarry to see “the big boy toys.”
Looking to the future
The future is looking pretty bright for Sloan Quarry. “The construction market is rebounding, and we’re starting to see our volumes grow,” Priest notes. “The residential and multi-family infrastructure sector is coming back big time in this market now. We’re venturing out west where we have a good relationship with the Howard Hughes Corp. that owns all the property on the west side of town. A new golf course is going in, and they’re talking about high-speed rail between here and California to help with future traffic.”
“What sets us apart from everyone else is the team that we have, the commitment that we have, and how well we communicate,” Hancock says. “The future is exciting because we all work well together. Going forward, I think it’s going to be really good, because we have a good core team here.”